i. Let A (x1, y1) and B (x2, y2) be the given points.
∴ x1 = a, y1 = 0, x2 = 0, y2 = a
By distance formula,
∴ d(A, B) = a√2 units
ii. Let P (x1, y1) and Q (x2, y2) be the given points.
∴ x1 = -6, y1 = -3, x2 = -1, y2 = 9
By distance formula,
∴ d(P, Q) = 13 units
iii. Let R (x1, y1) and S (x2, y2) be the given points.
∴ x1 = -3a, y1 = a, x2 = a, y2 = -2a
By distance formula,
∴ d(R, S) = 5a units